10NL: TPTK facing raise on river

PokerStars - $0.10 NL (9 max) - Holdem - 7 players
Hand converted by PokerTracker 3

BTN: $10.00
SB: $11.43
BB: $12.77
Hero (UTG): $10.00
UTG+1: $11.96
MP: $7.50
CO: $9.80

Pre Flop: (pot: $0.15) Hero has K♦ A♠

Hero raises to $0.30, UTG+1 calls $0.30, fold, fold, fold, fold, fold

Flop: ($0.75, 2 players) 7♣ K♠ 5♣
Hero checks, UTG+1 checks

Turn: ($0.75, 2 players) 8♥
Hero bets $0.50, UTG+1 calls $0.50

River: ($1.75, 2 players) Q♦
Hero bets $1.20, UTG+1 raises to $2.40, Hero...

No real reads as it's in the first orbit of the session.
I would normally make a continuation bet on the flop with the flush draw out there, but was perhaps looking to check-raise.
What do you think it the best play for the river here?

Cheers.